The present invention relates to the installation of ground rods for grounding equipment associated with power distribution systems and particularly relates to a ground rod installation hammer and method of using the hammer.
Ground rods are typically used by utility companies to ground equipment associated with power distribution systems, e.g., high tension towers and light poles, so as to prevent damage caused by lightning, electrical surges, stray voltages and the like. Ground rods are typically formed of highly conductive material and driven into the ground to predetermined depths. Conventionally, the ground rods are driven into the ground by impacting devices, such as hammers. In my prior application, Ser. No. 757206 filed Sep. 10, 1991, now U.S. Pat. No. 5,174,388, issued Dec. 29, 1992, there is disclosed a mechanism for guiding and facilitating the insertion of the ground rod into the ground. In many applications, however, sledge hammers are often utilized as the means to drive the rod into the ground.
As a means for driving the rods into the ground, sledge hammers leave a lot to be desired. For example, typically an individual will hold the rod while another individual swings a sledge hammer intending the hammer head to impact on the upper end of the rod to drive the rod into the ground. Frequently, the individual swinging the sledge hammer misses the upper end of the rod and the sledge hammer impacts against the arm or hand of the individual holding the rod. Also, there is a substantial danger of striking the rod end with the sledge hammer off center. This may not only bend the rod but can deflect the sledge hammer toward or into the individual holding the rod. Thus, there is the very substantial danger of injury to individuals assisting in driving the rods into the ground when a sledge hammer is used. Moreover, the weight of the sledge hammer and, hence, its impact on the rod, is limited by the ability and strength of the individual when swinging the sledge hammer to swing the hammer accurately and impact the upper end of the rod. Too much weight inhibits the individual from swinging the sledge hammer accurately, while too little weight requires a substantial number of repetitive impacts of the hammer on the rod to drive the rod into the ground. The present invention avoids and overcomes many of these problems when a sledge hammer is used to manually drive the rod into the ground.
According to the present invention, there is provided a tool in the nature of a sledge hammer, but having various modifications and adaptations to facilitate the impacting a ground rod with substantial weight without bending or missing the rod or only partially impacting the rod when it is being driven. Additionally, the present invention provides a tool which, when used as a sledge hammer, does not require another individual to hold the rod. It also improves the accuracy of the impact on the rod when swinging the tool as a sledge hammer and minimizes any tendency of the tool to be deflected when the rod is struck slightly off-center.
For this purpose, the tool of the present invention comprises a handle having a sleeve defining a bore opening through the handle at one end for receiving the upper end of a rod to be driven into the ground. The end of the handle about the bore opening is flared outwardly to prevent the operator's hand from slipping off the handle when using the tool as a slide hammer and as a sledge hammer, as well as to facilitate reception of the upper end of the rod within the bore. The handle includes a sleeve defining the bore and a solid shank secured to the end of the sleeve opposite the handle opening, the end of the shank serving as a striking surface as described hereinafter. The opposite end of the handle mounts a hammer head and a weight. Preferably, the hammer head and weight are generally of similar configuration in length, width and height with each having a generally hexagonally cross-sectional shape. The hammer head is secured to the opposite end of the handle in any convenient manner, similarly as sledge hammer heads are typically secured to handles, for example, by welding.
The weight is removably mounted on the tool adjacent the hammer head end of the tool. Particularly, the shank handle has an internally threaded bore. The weight also includes a bore for receiving a bolt whereby the bolt may be threaded into the shank of the handle to removably mount the weight to the tool. To prevent the weight from rotating about the bolt and relative to the adjacent hammer head, one or more pins are disposed in registering apertures in the weight and hammer head to maintain the weight and the hammer head aligned one with the other.
An important feature of the present invention, as will become clear from the following description, resides in the provision of a longitudinally extending aperture formed in the weight opening through an end face of the weight. The diameter of the aperture is such that the weight, when removed from the tool, can be disposed on the rod end with the rod end being received within the aperture. In this manner, the opposite end face of the weight may serve as a striking surface for the tool when used as a sledge hammer.
In use, the tool, with the weight secured to the hammer head end of the tool, is applied over the rod to be inserted into the ground such that the upper end of the rod is received in the handle bore. By repeatedly raising and lowering the tool and repeatedly striking the upper end of the rod with the impact surface of the shank within the bore of the handle, the rod may be driven into the ground. The handle sleeve defining the bore provides a guide for the tool during this slide hammering action. When the rod has been driven into the ground as deep as the handle permits, and greater impact forces are necessary to further drive the rod into the ground, the tool is lifted and removed from the rod. The bolt securing the weight to the tool head is unthreaded and the weight is removed from the tool. The weight is then applied to the upper end of the ground rod by inserting the weight over the rod end, i.e., the rod end being received within the aperture of the weight. The opposite end face of the weight then serves upwardly facing as an impact surface carried by the rod. The tool can then be employed as a sledge hammer and the rod driven into final engagement into the ground by impacting the hammer head against the end face of the weight carried by the rod.
It will be appreciated from the foregoing description that the slide hammering action impact force initially applied to the rod when the rod lies within the sleeve does not require another individual to hold the rod. The handle sleeve serves as a guide for this slide hammering action. Additionally, greater impact is provided on the rod by the combined weight of the hammer head and weight attached thereto during this slide hammering action than might otherwise occur by swinging a conventional sledge hammer. Further, when a sledge hammer action is necessary, the end face of the weight serves as an additional and enlarged head against which the head of the tool may be impacted. Thus, the sledge hammer can be swung with greater accuracy, and with less danger of the rod bending or the tool deflecting upon impact.
In a preferred embodiment it is a tool for installing a rod into the ground comprising a handle having a bore opening at one of the handle for receiving the rod; a hammer head secured to said handle adjacent its opposite end; a weight carried by said tool adjacent said opposite end of said handle and said hammer head such that, upon disposition of the tool over an end of the rod and reception of the end of the rod within said bore, the tool may be raised and lowered along the rod to hammer the rod in the ground; and means for removably mounting said weight on said tool whereby, upon removal of the weight, the tool may be swung as a sledge hammer to further drive the rod into the ground.
In a further preferred embodiment, it is a method of driving a rod into the ground using a tool having an elongated handle with a bore opening at one end of the handle and a head and removable weight adjacent the opposite end of the handle, comprising the steps of disposing the tool over the rod with the end of the rod received within the bore of the handle; repeatedly raising and lowering the tool with the weight attached to drive the rod into the ground; thereafter, removing the tool from the rod; removing the weight from the tool; disposing the weight on the rod with the end of the rod received within an aperture formed on the weight; and striking the weight with the hammer head to further drive the rod into the ground.
Accordingly, it is primary object of the present invention to provide a novel and improved ground rod installation tool and method of use which minimizes or eliminates many of the dangers inherent in the use of a sledge hammer while facilitating insertion of the rod into the ground.